21213444056550 has 96 divisors (see below), whose sum is σ = 54065788568064. Its totient is φ = 5501198496000.

The previous prime is 21213444056537. The next prime is 21213444056557. The reversal of 21213444056550 is 5565044431212.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213444056557) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3632914 + ... + 7458213.

It is an arithmetic number, because the mean of its divisors is an integer number (563185297584).

Almost surely, 2^{21213444056550} is an apocalyptic number.

21213444056550 is an abundant number, since it is smaller than the sum of its proper divisors (32852344511514).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21213444056550 is a wasteful number, since it uses less digits than its factorization.

21213444056550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11091494 (or 11091489 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 42.

Adding to 21213444056550 its reverse (5565044431212), we get a palindrome (26778488487762).

The spelling of 21213444056550 in words is "twenty-one trillion, two hundred thirteen billion, four hundred forty-four million, fifty-six thousand, five hundred fifty".